Thinking inside the graft: applications of optical coherence tomography in coronary artery bypass grafting

Recent advances in catheter-based optical coherence tomography (OCT) have provided the necessary resolution and acquisition speed for high-quality intravascular imaging. Complications associated with clearing blood from the vessel of a living patient have prevented its wider acceptance. We identify a surgical application that takes advantage of the vascular imaging powers of OCT but that circumvents the difficulties. Coronary artery bypass grafting (CABG) is the most commonly performed major surgery in America. A critical determinant of its outcome has been postulated to be injury to the conduit vessel incurred during the harvesting procedure or pathology preexistent in the harvested vessel. As a test of feasibility, intravascular OCT imaging is obtained from the radial arteries (RAs) and/or saphenous veins (SVs) of 35 patients scheduled for CABG. Pathologies detected by OCT are compared to registered histological sections obtained from discarded segments of each graft. OCT reliably detects atherosclerotic lesions in the RAs and discerns plaque morphology as fibrous, fibrocalcific, or fibroatheromatous. OCT is also used to assess intimal trauma and residual thrombi related to endoscopic harvest and the quality of the distal anastomosis. We demonstrate the feasibility of OCT imaging as an intraoperative tool to select conduit vessels for CABG.